convert images

[nkoss]

Oh no...not another one...sorry

On disk A, in the convert images movie, the process is clear and no trouble...2 questions...

1) Why, if you are going to PRINT, do you convert to a JPG, rather than a TIFF or PSD (lossless)?

2) Normally in ACR, I keep the output resolution at 300, but I see now that if you don't actually SAVE, but rather choose DONE as we did, the resolution remains what it was when the images came in from the camera, which for most cameras is 72. It turns out that the converted images from iView are actually OK for printing 4x6 at 300, but they need to go through an 'image resize' in Photoshop first

[peterkrogh]

Neal,
1. You can do either.  In the vast majority of cases, there will be no visible difference between printing from a best quality JPEG and printing from a TIFF.  If you are printing directly from the embedded preview in a DNG, then you are accessing JPEG data anyway.  I suggest you do a test if you are doubtful.

2. First, the resolution settings in ACR are *output* settings, and are not saved in the RAW file in any way. Second, I don't think you will need to resize the images in Photoshop after output with iView.  You can resize and change resolution in iView, although I have found that the PPI part does not always seem to be reliably applied.  In any case, the need to do an Image Resize in Photoshop would be dependent on the method of printing.  Have you tried to go to print without changing the PPI?

Peter

[nkoss]

1) That is certainly different from what many of the other teachers are saying. Which means to me that it probably doesn't matter (as long as it is high quality JPG)

2)I haven't had time to test, but I always thought and again, was taught, that printing should not be done at less than 240 ppi. Thus if you just print the converted image directly, you are printing at 72, which is 'monitor-resolution' not usually for printing. Are you going to burst that bubble, too??? 

[peterkrogh]

Neal,
1. JPEG is not a great storage format for master images, but it's perfectly fine for lots of delivery uses.  You can always do the subtraction test.
Open a TIFF.
Save out a JPEG.
Copy the JPEG data.
Paster in a Layer
Set Belending mode to Difference, and you will see any different pixels.
Very few, generally.

Or you can print from both and see if you see a difference.

Many trainers will exaggerate the loss with JPEGs so that you are not tempted to store master files this way.  THis was certainly more of an issue in the infancy of digital imaging, and when storage was expensive.

2. In most cases, the printing device can be made to size correctly, despite the nominal PPI setting.  So a file that is 100 inches at 30 PPI will print exactly the same as a file 10 inches at 300 PPI.  It would only be necessary to open in Ps and resize if the print device/software/mechanism could not do the resize to the image.  Most printing systems provide you a way to specify print size without first making those setting in Ps.

And, no, I am not saying that you will get as good a print 8x10 @ 72 PPI as 8x10 @ 300 PPI. It's ust that you probably don't need Photoshop to do this specifying.
Peter